what surface do you have it on when you're using it? try putting it on blocks so that it's somewhat elevated to increase airflow. if you've got it plugged into the mains, take the battery out, and turn the entire thing off everynow and then. leaving it on constantly or only putting it into standby will make your computer work harder which makes it work hotter.

compressed air through vents to clean it out

cool a tub of cooking oil down to about 3 degrees celcius (below 0 it will start to crystalise) and submerge your laptop while you run it for a bit. you probably want to seran wrap the keyboard otherwise you could have oily keys for a while. cooking oil is non conductive, and like car oil will clean, lubricate and protect against heat damage. you can also use real motor oil but it has to be really thin, and it'd probably cost a fortune, whereas cooking oil has a high flashpoint, is cheap, and will smell like popcorn rather than an engine when it starts to evaporate.

if you are man enough take it to bits, hoover it out and put it back together

i know a guy with an alienware laptop that ran like shit until he did this

Taking apart your laptop can void some warranties, be careful. If your system is still under warranty, you may even be able to send it in over "extreme heating issues". You may even get some more helpful ideas and advice from calling the manufacturer.

Here's a few suggestions I just thought about in order of practicality

• Buy a laptop cooler. Be sure to check the reviews and noise rating before checking out.
  
• Reduce your games' video quality
• Underclock your CPU